Reviewer:

I really wanted this recipe to be great - but it was a disaster! I should have known something would go wrong since onions give off a lot of water/juices when they cook! The end result was NOT a traditional "au gratin" dish but more of cheesy soupy onion mess. It was hardly edible and a great disappointment (not to mention waste of perfectly good onions)! My only recommendation/suggestion for fixing this would be to bake the onions first without the mixture - pour off the excess liquid - then add the flour/cream mixture and cheeses and bake again... that's the only thing that comes to mind to avoid the soup I ended up with. However, with that said - I will NOT be making this again!